I think that is going to be a nice ray..
I would talk to whoever is in charge, and explain to them that this is a damaged ray and offer them $100 cash..
I would also find a large source of blackworms.. have a large empty cycled aquarium at about 82-84 degrees, lightly salted, extra o2, ready to go for them.. feed blackworms/nightcrawlers heavily and hope they regenerate their disc and put on some weight.